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Output Ports

Port Number (hex) Equate Function Notes
0 COL0R Color Register 0 (Right)
1 COL1R Color Register 1
2 COL2R Color Register 2
3 COL3R Color Register 3
4 COL0L Color Register 0 (Left)
5 COL1L Color Register 1
6 COL2L Color Register 2
7 COL3L Color Register 3
8 CONCM Low/High Resolution Always Low on Astrocade
9 HORCB Horizontal Color Boundary (bits 0–6), BG Color (bits 6–7)
A VERBL Vertical Blank Register # of vertical lines x 2 to be used for screen update)
B COLBX Color Block Transfer
C MAGIC Magic Register
D INFBK Interrupt Feedback 8 bits of vector to be returned by interrupting device upon receipt of INTAK from Z80)
E INMOD Interrupt Enable and Mode Always 8 in cartridges
F INLIN Interrupt Line
10 TONMO Tone Master Oscillator
11 TONEA Tone A Frequency
12 TONEB Tone B Frequency
13 TONEC Tone C Frequency
14 VIBRA Vibrato/Tremolo
15 VOLAB Tone C Volume, Noise Modulation Control
16 VOLC Tone A Volume, Tone B Volume
17 VOLN Noise Volume
18 SNDBX Sound Block Transfer
19 XPAND Expander Pixel Definition

[NM:106, 143, source listing 5]